/*
 * The copyright in this software is being made available under the 2-clauses
 * BSD License, included below. This software may be subject to other third
 * party and contributor rights, including patent rights, and no such rights
 * are granted under this license.
 *
 * Copyright (c) 2002-2014, Universite catholique de Louvain (UCL), Belgium
 * Copyright (c) 2002-2014, Professor Benoit Macq
 * Copyright (c) 2001-2003, David Janssens
 * Copyright (c) 2002-2003, Yannick Verschueren
 * Copyright (c) 2003-2007, Francois-Olivier Devaux
 * Copyright (c) 2003-2014, Antonin Descampe
 * Copyright (c) 2005, Herve Drolon, FreeImage Team
 * Copyright (c) 2008, Jerome Fimes, Communications & Systemes <jerome.fimes@c-s.fr>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __MQC_INL_H
#define __MQC_INL_H
/**
FIXME DOC
@param mqc MQC handle
@return
*/
static INLINE OPJ_INT32 opj_mqc_mpsexchange(opj_mqc_t *const mqc)
{
    OPJ_INT32 d;
    if (mqc->a < (*mqc->curctx)->qeval) {
        d = (OPJ_INT32)(1 - (*mqc->curctx)->mps);
        *mqc->curctx = (*mqc->curctx)->nlps;
    } else {
        d = (OPJ_INT32)(*mqc->curctx)->mps;
        *mqc->curctx = (*mqc->curctx)->nmps;
    }

    return d;
}

/**
FIXME DOC
@param mqc MQC handle
@return
*/
static INLINE OPJ_INT32 opj_mqc_lpsexchange(opj_mqc_t *const mqc)
{
    OPJ_INT32 d;
    if (mqc->a < (*mqc->curctx)->qeval) {
        mqc->a = (*mqc->curctx)->qeval;
        d = (OPJ_INT32)(*mqc->curctx)->mps;
        *mqc->curctx = (*mqc->curctx)->nmps;
    } else {
        mqc->a = (*mqc->curctx)->qeval;
        d = (OPJ_INT32)(1 - (*mqc->curctx)->mps);
        *mqc->curctx = (*mqc->curctx)->nlps;
    }

    return d;
}

/**
Input a byte
@param mqc MQC handle
*/
static INLINE void opj_mqc_bytein(opj_mqc_t *const mqc)
{
    /* Implements ISO 15444-1 C.3.4 Compressed image data input (BYTEIN) */
    /* Note: alternate "J.3 - Inserting a new byte into the C register in the */
    /* software-conventions decoder" has been tried, but does not bring any */
    /* improvement. See https://github.com/uclouvain/openjpeg/issues/921 */
    if (mqc->bp != mqc->end) {
        OPJ_UINT32 c;
        if (mqc->bp + 1 != mqc->end) {
            c = *(mqc->bp + 1);
        } else {
            c = 0xff;
        }
        if (*mqc->bp == 0xff) {
            if (c > 0x8f) {
                mqc->c += 0xff00;
                mqc->ct = 8;
            } else {
                mqc->bp++;
                mqc->c += c << 9;
                mqc->ct = 7;
            }
        } else {
            mqc->bp++;
            mqc->c += c << 8;
            mqc->ct = 8;
        }
    } else {
        mqc->c += 0xff00;
        mqc->ct = 8;
    }
}

/**
Renormalize mqc->a and mqc->c while decoding
@param mqc MQC handle
*/
static INLINE void opj_mqc_renormd(opj_mqc_t *const mqc)
{
    do {
        if (mqc->ct == 0) {
            opj_mqc_bytein(mqc);
        }
        mqc->a <<= 1;
        mqc->c <<= 1;
        mqc->ct--;
    } while (mqc->a < 0x8000);
}

/**
Decode a symbol
@param mqc MQC handle
@return Returns the decoded symbol (0 or 1)
*/
static INLINE OPJ_INT32 opj_mqc_decode(opj_mqc_t *const mqc)
{
    /* Implements ISO 15444-1 C.3.2 Decoding a decision (DECODE) */
    /* Note: alternate "J.2 - Decoding an MPS or an LPS in the */
    /* software-conventions decoder" has been tried, but does not bring any */
    /* improvement. See https://github.com/uclouvain/openjpeg/issues/921 */
    OPJ_INT32 d;
    mqc->a -= (*mqc->curctx)->qeval;
    if ((mqc->c >> 16) < (*mqc->curctx)->qeval) {
        d = opj_mqc_lpsexchange(mqc);
        opj_mqc_renormd(mqc);
    } else {
        mqc->c -= (*mqc->curctx)->qeval << 16;
        if ((mqc->a & 0x8000) == 0) {
            d = opj_mqc_mpsexchange(mqc);
            opj_mqc_renormd(mqc);
        } else {
            d = (OPJ_INT32)(*mqc->curctx)->mps;
        }
    }

    return d;
}

#endif /* __MQC_INL_H */
